1. Field of the Invention
This invention relates to a tray for dispensing dental materials and is especially suitable for dispensing dental materials that are curable upon exposure to light.
2. Description of the Related Art
Photocurable dental materials have become increasingly popular in recent years. An example of light curable dental material includes the Scotchbond brand multi-purpose dental adhesive system available from the assignee of the present invention. The Scotchbond brand adhesive system includes an etchant for etching tooth enamel or dentin surfaces, a primer to facilitate wetting of the adhesive on the prepared tooth structure, and an adhesive that bonds to either etched enamel or dentin. Both the primer and the adhesive rapidly cure upon exposure to light in the visible spectrum.
A light curing unit is normally used to cure dental material. Such light curing units are hand-held by the user to enable the light to be directed into the oral cavity and toward the dental material when desired. Photocurable dental materials are advantageous because the material can be positioned exactly where desired and excess material can be removed before the light curing unit is activated to cure the material.
Photocurable dental materials are often sold in bulk in a dropper bottle, syringe or other container. Typically, a small quantity of the material is transferred from the container to a well of a dispensing tray adapted for use for a single patient, so that the likelihood of contamination of material in the bulk container is reduced. A brush or other tool is used to transfer material from the well to the tooth structure of the patient. The dispensing tray is then cleaned and sterilized before use for another patient.
It has been observed in the past that the background lighting of dental operatories is often sufficient to prematurely polymerize certain photocurable dental materials if left exposed for a sufficient amount of time. To avoid such an occurrence, the dispensing tray may be temporarily covered with an opaque sheet to prevent at least some of the visible light from reaching dental material in wells of the tray. Alternatively, a dispensing tray with an opaque cover can be used, such as the dispensing tray with a hinged cover that is described in U.S. Pat. No. 5,139,188. A dispensing tray having an opaque sliding cover is described in U.S. Pat. No. 4,822,280.
Some photocurable dental materials have a relatively low viscosity and thus may easily overflow from the well of the dispensing tray if the tray is unduly tilted or jostled during use. Unfortunately, such an event may cause the material to be spilled onto the floor or otherwise wasted, or enter an adjoining well where it may undesirably mix with another dental material.